1. Field of the Invention
The present invention relates to an optical coordinate measuring device using a contact-type probe.
2. Description of Related Art
A contact-type coordinate measuring device is provided with a probe having a contact part. The contact part of the probe is brought into contact with a measurement target, and coordinates of a contact position between the measurement target and the contact part are calculated. By calculating coordinates of a plurality of positions on the measurement target, a size of a desired portion of the measurement target is measured.
JP 06-511555 A describes a system for point by point measurement of spatial coordinates, which includes a data processor, a contact probe, and an angle sensor. The contact probe is provided with a plurality of point light sources in addition to a contact point. The angle sensor is provided so as to allow observation of an essential portion of a measurement target and allow observation of the plurality of point light sources of the contact probe.
A spatial direction from the angle sensor toward each light source is recorded. Based on the recorded spatial direction, a position and an orientation of the contact probe with respect to the angle sensor are calculated by a data processor. The position of the contact probe and a position of the contact point are associated with a position of the measurement target.
In the system for point by point measurement in JP 06-511555 A, it is necessary to fix the angle sensor by use of a fixing tool such as a tripod so as to allow observation of the target and the plurality of point light sources of the contact probe. Hence, it is possible to efficiently measure a shape of a relatively large-sized measurement target. However, in the case of measuring a shape of a relatively small-sized measurement target, performing a procedure of preparing the fixing tool, fixing the angle sensor, and the like causes deterioration in measurement efficiency. Further, when an attempt is made to realize high measurement accuracy such as several μm to several tens of μm by means of an optical measuring device, a measurement target range is relatively restricted. This makes adjustment of the fixing tool such as the tripod to take time or makes it hard for a user to recognize the measurement target range. These also become the cause of deterioration in measurement efficiency.